Vehicles having a spark ignited piston engine as a power source use gasoline as a fuel source. Previously, leaded gasoline included Tetra-ethyl lead (TEL) as an additive to improve the octane of the fuel. However, lead was identified as a neurotoxin and its phase out began in the 1970s. TEL was completely banned by the Environmental Protection Agency (EPA) for use in gasoline targeted for automotive vehicles in 1995. Presently, General Aviation (GA) aircrafts having a spark-ignited piston engine utilize leaded gasoline as a fuel source. To date, aviation gasoline (av-gas) has been exempt from the mandatory lead phase out because of the aviation industry's inability to come up with an unleaded gasoline that could satisfy the octane needs of all current engines used for aviation purposes.
While the grade 94 unleaded (94UL) av-gas governed by ASTM D7592 standard is currently approved for commercial sale, its use is limited to low compression engines due to the lower octane rating of the fuel. The performance needs of a higher horsepower normally aspirated engine, such as a 300 hp engine with 8.5:1 compression ratio, are not satisfied by the 94UL fuel because of the lower Motor Octane (MON) rating of 94UL fuel.
Every fuel, including those designated as leaded aviation gasoline i.e. grade 80, grade 91, grade 100, grade 100LL or grade 100VLL, must satisfy a predetermined ASTM standard, which in the case of av-gas is D910. ASTM standard D910 establishes limits on predetermined parameters and performance specifications that the fuel must meet. For example, ASTM standard D910 sets the maximum level of lead allowable in a particular grade of av-gas, but does not set the limits on the minimum lead content. The maximum TEL allowed has been lowered from 4.0 mL TEL/gal (grade 100) to 2.0 mL/gal (grade 100LL) to 1.63 mL/gal (grade 100VLL). Grade 100VLL is identical to grade 100LL in all aspects, except maximum lead content is reduced by only 19%.
Any new fuel must undergo rigorous testing to insure compliance with the D910 standard. If a new fuel deviates from this standard, then there may be additional fuel certification costs, as measured in time and money. There could also be consumer costs due to possible modifications required by engines already in use.
Thus, there is a need in the art for a high octane non-leaded or ultra low leaded (i.e. 0-1.6 TEL/gal) replacement gasoline that is formulated to already be in compliance with the ASTM 910 standard for aviation fuel and is available for aviation purposes.